cosh(3) Library Functions Manual cosh(3) NAME cosh, coshf, coshl - hyperbolic cosine function LIBRARY Math library (libm, -lm) SYNOPSIS #include <math.h> double cosh(double x); float coshf(float x); long double coshl(long double x); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): coshf(), coshl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE DESCRIPTION These functions return the hyperbolic cosine of x, which is defined mathematically as: cosh(x) = (exp(x) + exp(-x)) / 2 RETURN VALUE On success, these functions return the hyperbolic cosine of x. If x is a NaN, a NaN is returned. If x is +0 or -0, 1 is returned. If x is positive infinity or negative infinity, positive infinity is returned. If the result overflows, a range error occurs, and the functions return +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL, respectively. ERRORS See math_error(7) for information on how to determine whether an error has occurred when calling these functions. The following errors can occur: Range error: result overflow errno is set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌─────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├─────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤ │cosh(), coshf(), coshl() │ Thread safety │ MT-Safe │ └─────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘ STANDARDS C99, POSIX.1-2001, POSIX.1-2008. The variant returning double also conforms to SVr4, 4.3BSD. BUGS In glibc 2.3.4 and earlier, an overflow floating-point (FE_OVERFLOW) exception is not raised when an overflow occurs. SEE ALSO acosh(3), asinh(3), atanh(3), ccos(3), sinh(3), tanh(3) Linux man-pages 6.03 2023-02-05 cosh(3)